Coordination of the cytoskeletons of neighboring cells is an important component of morphogenesis during development. As a model system to study this coordination, I am using the Drosophila epidermis, a tissue which contains large numbers of hairs and bristles. These are polarized structures formed from cytoskeletal-mediated projections of epidermal cells. Hairs and bristles are normally aligned in parallel giving the tissue a distinct polarity. It is my long term goal to understand on a molecular level how this is achieved, and what the role of individual genes and gene products are in the process. I have been genetically examining a particular genetic locus (frizzled (fz)) that appears to be involved in the development of tissue polarity. Mutations in this gene disrupt normal tissue polarity. Thus, for example, hairs and bristles no longer point in parallel from proximal to distal on appendages. This proposal is primarily concerned with a molecular characterization of the gene and its products. I propose to develop a detailed map of the fz transcription unit, primarily via a cDNA clone analysis. The fz protein sequence will be deduced from sequencing a cDNA clone. Monoclonal antibodies to the fz protein will be isolated using, as an antigen, material made in an expression vector. The antibodies will be used to characterize the tissue and cellular distribution of fz gene products in wild type and mutant tissue.